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[Primary research of development of a mouse model for non-bacterial sialoadenitis]

OBJECTIVE: To develope a mouse model for non-bacterial sialoadenitis similar to SS.The model of organ-specific to the submandibular gland of mouse has developed for this study. METHODS: Several of the mouse strains were used to the development of non-bacterial sialoadenitis.The injection of syngeneic salivary gland tissue with CFA induced inflammation in submandibular gland in mice.Not all mice had a predictable response. RESULTS: C(57) mice (500microg/ml and 750microg/ml group )appear histologically to be more prove to develop sialoadenitis. CONCLUSION: An animal model of non-bacterial sialoadenitis had been set up,the non-bacterial sialoadentitis may be similar to the autoimmune process in human SS.

Journal Article↗

Amyloid-beta immunization in Alzheimer's disease transgenic mouse models and wildtype mice.

Alzheimer's disease is the most prevalent form of dementia worldwide. Therapies are desperately needed to prevent and cure the disease. Mouse models of amyloid-beta deposition [APP and PSAPP transgenic (tg) mice] have been useful in determining the role of amyloid-beta (A beta) in both the pathogenesis and cognitive changes in AD. In addition, they have allowed scientists to investigate potential AD therapies in living animals. Active and passive A beta immunizations have been employed successfully in APP and PSAPP tg mice to lower cerebral A beta levels and improve cognition. Optimization of immunization protocols and characterization of immune responses in wildtype mice have been reported. Based on the promising results of A beta immunization studies in mice, a clinical trial was initiated for A beta vaccination in humans with AD. Although no adverse effects were reported in the Phase I safety trials, about 5% of AD patients in the phase II clinical trial developed meningoencephalitis, ending the trial prematurely in March 2002. Studies in AD mouse models and wildtype mice may help elucidate the mechanism for these unwanted side effects and will be useful for testing newer, safer vaccines for future use in human clinical trials.

Alzheimer Disease↗

Cerebral protein synthesis in a genetic mouse model of phenylketonuria.

Local rates of cerebral protein synthesis (lCPS(leu)) were measured with the quantitative autoradiographic [1-(14)C]leucine method in a genetic mouse model (Pah(enu2)) of phenylketonuria. As in the human disease, Pah(enu2) mice have a mutation in the gene for phenylalanine hydroxylase. We compared adult homozygous (HMZ) and heterozygous (HTZ) Pah(enu2) mice with the background strain (BTBR). Arterial plasma concentrations of phenylalanine (Phe) were elevated in both HMZ and HTZ mutants by 21 times and 38%, respectively. In the total acid-soluble pool in brain concentrations of Phe were higher and other neutral amino acids lower in HMZ mice compared with either HTZ or BTBR mice indicating a partial saturation of the l-amino acid carrier at the blood brain barrier by the elevated plasma Phe concentrations. In a series of steady-state experiments, the contribution of leucine from the arterial plasma to the tRNA-bound pool in brain was found to be statistically significantly reduced in HMZ mice compared with the other groups, indicating that a greater fraction of leucine in the precursor pool for protein synthesis is derived from protein degradation. We found reductions in lCPS(leu) of about 20% throughout the brain in the HMZ mice compared with the other two groups, but no reductions in brain concentrations of tRNA-bound neutral amino acids. Our results in the mouse model suggest that in untreated phenylketonuria in adults, the partial saturation of the l-amino acid transporter at the blood-brain barrier may not underlie a reduction in cerebral protein synthesis.

Animals↗

Comparative influence of steroid hormones and immunosuppressive agents on autoimmune expression in lacrimal glands of a female mouse model of Sjögren's syndrome.

PURPOSE: Previous research has demonstrated that testosterone therapy causes a profound suppression of autoimmune disease in lacrimal glands of female mouse models of Sjögren's syndrome. The aim of the present study was to determine whether other anabolic androgens, nonandrogenic steroids, or immunosuppressive agents might duplicate this hormonal effect. For comparative purposes, we also evaluated the influence of these various pharmacologic compounds on the tear volume, the magnitude of lymphocyte infiltration in the submandibular gland, and the extent of mucosal and peripheral lymphadenopathy. METHODS: Female MRL/MpJ-lpr/lpr mice were administered vehicle, steroids, or immunosuppressive compounds for 21 days after the onset of disease. Lacrimal glands and tears, as well as submandibular glands, spleens, and superior cervical and mesenteric lymph nodes were collected immediately before or after treatment and then processed for analysis. RESULTS: Our results showed that: (1) the immunosuppressive impact of testosterone on lymphocyte infiltration in lacrimal tissue was reproduced by the administration of 19-nortestosterone or cyclophosphamide, but not by therapy with 17 beta-estradiol, danazol, the experimental steroid Org 4094, cyclosporine A or dexamethasone; (2) treatment with testosterone, 19-nortestosterone, cyclophosphamide, or dexamethasone significantly reduced the extent of inflammation in salivary glands; (3) exposure to cyclophosphamide markedly diminished the size of lymphatic and splenic tissues, whereas glucocorticoid treatment only decreased the weight of superior cervical lymph nodes; and (4) administration of 17 beta-estradiol, Org 4094, or dexamethasone led to a significant decrease in tear volume. CONCLUSIONS: Overall, these results demonstrate that androgen or cyclophosphamide therapy may successfully ameliorate autoimmune expression in lacrimal and salivary glands of a female mouse model of Sjögren's syndrome.

Animals↗

Age, environment, and lymphocyte immunization influence the spontaneous resorption rate in the CBA/J x DBA/2J mouse model.

PROBLEM: This study was designed to examine the influence of age, environment, and lymphocyte immunotherapy on fetal resorption rates in the CBA/J x DBA/2J mouse model. METHODS: After weaning, CBA/J female mice were randomly allocated to two different environments: room A was a conventional housing facility, and room B was a specific pathogen-free room. They were further divided into two groups in each room according to age (> three months and < or = three months), and mated with CBA/J, DBA/2J, or BALB/c males. The fetal resorption rates were observed. The immunization study was conducted using CBA/J females greater than three months old in room B. Preimmunization with various preparations and dosages of lymphocytes was performed 1 wk before mating with DBA/2J males, and fetal resorption rates were measured to investigate the effect of immunotherapy. RESULTS: In room A, the fetal resorption rates (9.4 to 11.8%) were not significantly different among the various mating combinations using CBA/J females greater or less than three months of age. In room B, CBA/J females older than three months and mated with DBA/2J males had a higher rate of fetal resorption than those younger than three months (28.9 versus 14.2%) and had higher rate of fetal resorption than those housed and mated in room A (28.9 versus 10.9%). This fetal resorption rate was also higher than those seen with other mating combinations. Preimmunization with male BALB/c splenic lymphocytes (optimal dose 1 x 10(7) cells) was effective in decreasing fetal resorption rate (7.9%), whereas administration of normal saline, or immunization with male CBA/J or DBA/2J lymphocytes was not (20.7 to 27.0%). CONCLUSION: Age and environment influence the spontaneous resorption rate in the CBA/J x DBA/2J mouse model. The high fetal resorption rate of older CBA/J females mated with DBA/2J males in a pathogen-free environment can be reduced by immunization with BALB/c splenic lymphocytes. These results suggested that a variety of mechanisms might initiate early pregnancy failure and that immunological modulation during implantation might be a nonspecific factor.

Abortion, Spontaneous↗

Effect of thyroid hormone and sex status on epidermal growth factor concentrations in the submandibular gland of a congenitally hypothyroid mouse model.

Studies were performed to explore the role of thyroid hormone and sex status on epidermal growth factor concentrations in the submandibular gland of a congenitally hypothyroid mouse model designated hyt/hyt. The animals were studied at 20, 30 and 40 days of postnatal age. The euthyroid animals were homozygous or heterozygous for the hypothyroid gene. The homozygous euthyroid animals displayed a pattern of submandibular gland epidermal growth factor concentrations similar to those previously described in other mouse species and showed the expected sex differences. The hypothyroid animals had measurable but very low submandibular gland epidermal growth factor concentrations without sexual dimorphism. Serum thyroxine concentrations in the heterozygotes were comparable to those in the homozygous euthyroid animals, yet the animals had a delayed increase in epidermal growth factor concentrations combined with a later expression of female-male differences. The timing of the sex differences in submandibular gland epidermal growth factor concentrations followed a pattern similar to that seen for the timing of the first litter in these three genetically distinct groups. This infers the timing of the onset of puberty and suggests a role of androgens in the changes seen in epidermal growth factor concentrations. We conclude that thyroid hormone and sex status in this mouse model influence the pattern and concentrations of submandibular gland epidermal growth factor concentrations.

Animals↗

Allergen-induced bronchial hyperreactivity and eosinophilic inflammation occur in the absence of IgE in a mouse model of asthma.

In patients with asthma, elevations of IgE correlate both with allergic inflammation of the airways and with bronchial hyperreactivity (BHR). Several investigations, using mouse models of this disease, have indicated a central role for IgE in the pathogenesis of the eosinophilic inflammation as well as in the obstructive airway physiology of BHR. Some diagnostic studies and therapeutic strategies for asthma are based on the putative role of IgE in asthma pathogenesis. Here, we use mice with a null mutation of the C epsilon locus to show that bronchial inflammation and BHR in response to allergen inhalation both can occur in the absence of IgE. We demonstrate that the eosinophilic bronchial inflammation elicited in an established mouse model of hypersensitivity to Aspergillus fumigatus (Af) is accompanied by the asthmatic physiology of BHR. Wild-type and IgE-deficient mice were sensitized intranasally with Af extract. Both groups of animals developed bronchoalveolar lavage eosinophilia and pulmonary parenchymal eosinophilia. This was accompanied by increased serum levels of total and Af-specific IgE in the wild-type animals only. This Af-sensitization protocol resulted in significant BHR in both wild-type mice and IgE-deficient mice. Interestingly, unsensitized IgE-deficient mice had increased bronchial responsiveness compared with unsensitized wild-type controls. We conclude that BHR and airways inflammation can be fully expressed via IgE-independent mechanisms. These may involve the activation of mast cells by factors other than IgE as well as a mucosal lymphocyte-mediated immune response to allergen.

Allergens↗

Mouse models for multistep tumorigenesis.

The mouse is an ideal model system for studying the molecular mechanisms underlying the pathogenesis of human cancer. The generation of transgenic and gene-knockout mice has been instrumental in determining the role of major determinants in this process, such as oncogenes and tumor-suppressor genes. In the past few years, modeling cancer in the mouse has increased in its complexity, allowing in vivo dissection of the fundamental concepts underlying cooperative oncogenesis in various tumor types. In this review, we discuss how this transition has been facilitated, providing relevant examples. We also review how, in the post-genome era, novel methodologies will further accelerate the study of multi-step tumorigenesis in the mouse.

Animals↗

Amplification of the neu/erbB-2 oncogene in a mouse model of mammary tumorigenesis.

The neu (c-erbB-2, Her-2) protooncogene is amplified and overexpressed in 20-30% of human breast cancers. Although transgenic mouse models have illustrated the role of Neu in the induction of mammary tumors, Neu expression in these models is driven by a strong viral promoter of questionable relevance to the human disease. To ascertain whether expression of activated Neu under the control of the endogenous promoter in the mammary gland could induce mammary tumors we have generated mice that conditionally express activated Neu under the transcriptional control of the intact endogenous Neu promoter. Expression of oncogenic neu in the mammary gland resulted in accelerated lobulo-alveolar development and formation of focal mammary tumors after a long latency period. However, expression of activated Neu under the normal transcriptional control of the endogenous promoter was not sufficient for the initiation of mammary carcinogenesis. Strikingly, all mammary tumors bear amplified copies (2-22 copies) of the activated neu allele relative to the wild-type allele and express highly elevated levels of neu transcript and protein. Thus, like human erbB-2-positive breast tumors, mammary tumorigenesis in this mouse model requires the amplification and commensurate elevated expression of the neu gene.

Animals↗

Selective neurodegeneration, without neurofibrillary tangles, in a mouse model of Niemann-Pick C disease.

The BALB/c mouse model of Niemann-Pick type C (NPC) disease exhibits neuropathological similarities to the human condition. There is an age-related cerebral atrophy, demyelination of the corpus callosum, and degeneration of cerebellar Purkinje cells in the NPC mouse. In human NPC, many cortical and subcortical neurons contain neurofibrillary tangles, which are thought by some investigators to play an important role in the neurodegenerative process. The purpose of the present study was to determine whether neurodegeneration occurs in the NPC mouse, in brain regions other than the cerebellum and whether the degeneration is related to the presence of neurofibrillary tangles. Using light microscopic methods with immunohistochemistry, electron microscopy, and cell counting methods, 11-week-old NPC(+/+) and NPC(-/-) animals were examined. In the NPC(-/-) mice, there were 96% fewer Purkinje cells, 28% fewer neurons in the prefrontal cortex, 20% fewer neurons in the thalamus, and 63% fewer glial cells in the corpus callosum. On the other hand, previous studies indicate normal numbers of neurons and glial cells in these same neuroanatomical regions in young NPC(-/-) mice. There were normal numbers of cholinergic neurons in sections assessed in the striatum and basal forebrain in the 11-week-old animals and no evidence of neurofibrillary tangles within cells. The present data indicate that both neurons and glial cells die in the NPC mouse but that all cells are not equally vulnerable. There was no evidence for neurofibrillary tangles in the NPC mouse, and therefore the degenerative process in the mouse is unrelated to the neurofibrillary tangle.

Animals↗

Mouse model of X-linked Alport syndrome.

X-linked Alport syndrome (XLAS) is a progressive disorder of basement membranes caused by mutations in the COL4A5 gene, encoding the alpha5 chain of type IV collagen. A mouse model of this disorder was generated by targeting a human nonsense mutation, G5X, to the mouse Col4a5 gene. As predicted for a nonsense mutation, hemizygous mutant male mice are null and heterozygous carrier female mice are mosaic for alpha5(IV) chain expression. Mutant male mice and carrier female mice are viable through reproductive age and fertile. Mutant male mice died spontaneously at 6 to 34 wk of age, and carrier female mice died at 8 to 45 wk of age, manifesting proteinuria, azotemia, and progressive and manifold histologic abnormalities of the kidney glomerulus and tubulointerstitium. Ultrastructural abnormalities of the glomerular basement membrane, including lamellation and splitting, were characteristic of human XLAS. The mouse model described here recapitulates essential clinical and pathologic findings of human XLAS. With alpha5(IV) expression reflecting X-inactivation patterns, it will be especially useful in studying determinants of disease variability in the carrier state.

Alleles↗

Mouse models of pancreatic cancer: the fur is finally flying!

Pancreatic cancer remains one of the most lethal of all human malignancies. Until recently, preclinical studies have been hampered by the absence of mouse models faithfully recapitulating critical elements of the human disease. However, recent months have witnessed a flurry of activity with respect to prospective mouse models. This progress now allows the evaluation of novel strategies for early detection, chemoprevention, and therapy and also provides new insights regarding the potential for differentiated and undifferentiated cell types to act as cells of origin for pancreatic ductal adenocarcinoma.

Animals↗

Interferon-gamma expression by intraepithelial lymphocytes results in a loss of epithelial barrier function in a mouse model of total parenteral nutrition.

OBJECTIVE: To determine the etiology of the loss of epithelial barrier function observed with the administration of total parenteral nutrition (TPN) in a mouse model. SUMMARY BACKGROUND DATA: Removal of enteral nutrition with the administration of TPN is associated with a loss of intestinal epithelial barrier function. The etiology of this barrier loss is not clear. Because intraepithelial lymphocytes (IELs) produce a number of cytokines that may alter epithelial permeability, the authors investigated IEL cytokine expression in a mouse model of TPN. METHODS: Adult C57BL/6 mice received TPN or enteral diet for 7 days. IELs were subsequently harvested and the mRNA expression of cytokines was measured. Epithelial barrier function was assessed in vitro with 51Cr-EDTA in Ussing chambers and was expressed as the permeability coefficient (Papp). RESULTS: IEL mRNA expression of interferon-gamma (IFN-gamma) rose from 0.14 +/- 0.07 in the control (enterally fed) group to 0.44 +/- 0.11 attomoles/microL in the TPN group (P <.05). Transforming growth factor-beta1 declined slightly but not significantly, from 0.75 +/- 0.35 to 0.55 +/- 0.18 attomoles/microL in the control and TPN groups, respectively. Epithelial barrier function declined significantly with TPN compared to controls. To assess the relevance of IFN-gamma changes, permeability in IFN-gamma knockout mice was studied. Barrier function was significantly higher in IFN-gamma knockout mice on TPN compared to C57BL/6 mice that received TPN. CONCLUSIONS: IEL cytokine expression changes significantly with TPN administration. The partial correction with IFN-gamma knockout mice suggests that an upregulation of IFN-gamma expression is one mechanism responsible for the loss of the epithelial barrier associated with TPN.

Animals↗

Anti-sclerotic effect of transforming growth factor-beta antibody in a mouse model of bleomycin-induced scleroderma.

Recent studies have demonstrated the evidence of the crucial role of transforming growth factor-beta (TGF-beta) in the pathogenesis of tissue fibrosis; however, its precise role has not been fully elucidated. Administration of anti-TGF-beta antibody is shown to be effective for inhibiting lung fibrosis induced by bleomycin in an experimental animal model. We have recently established a mouse model for scleroderma by repeated injections of bleomycin. In this study, we examined whether the suppression of TGF-beta leads to the improvement of dermal sclerotic lesion by using this model. We induced dermal sclerosis in C3H mice by subcutaneous injections of bleomycin (100 microg/ml) for 3 weeks, and separate groups of mice were also injected with bleomycin with either anti-TGF-beta antibody (10 microg/ml) or control normal rabbit serum for 3 weeks. Thus treated skins were harvested and analyzed for histological sclerosis, serum cytokine, and influx of mast cells and eosinophils, both of which are known to release fibrogenic cytokines or several mediators responsible for tissue fibrosis. The result showed that anti-TGF-beta antibody caused a significant reduction in cutaneous sclerosis characterized by histological features and hydroxyproline contents. Examination of tissue sections also revealed a significant suppression of influx of mast cells and eosinophils. Serum interleukin-4 (IL-4) and IL-6 levels determined by enzyme-linked immunosorbent assay exhibited a significant reduction after anti-TGF-beta antibody treatment. Our results suggest that administration of an antibody against TGF-beta is useful in preventing experimental dermal sclerosis induced by bleomycin and raises a possibility of the therapeutic approach of anti-TGF-beta antibody in scleroderma.

Animals↗

A heteroallelic mutant mouse model: A new orthologue for human hyperphenylalaninemia.

Hyperphenylalaninemias (HPA) are Mendelian disorders resulting from deficiencies in the conversion of phenylalanine to tyrosine. The vast majority are explained by a primary deficiency of phenylalanine hydroxylase (PAH) activity. The majority of untreated patients experience irreversible impairment of cognitive development. Although it is one of the best known hereditary metabolic disorders, mechanisms underlying the pathophysiology of the disease are still not fully understood; to this end, the availability of an orthologous animal model is relevant. Various mutant hyperphenylalaninemic mouse models with an HPA phenotype, generated by N-ethyl-N'-nitrosourea (ENU) mutagenesis at the Pah locus, have become available. Here we report a new hybrid strain, ENU1/2, with primary enzyme deficiency, produced by cross breeding. The ENU1, ENU1/2, and ENU2 strains display mild, moderate, and severe phenotypes, respectively, relative to the control strain (BTBR/Pas). The Pah enzyme activities of the various models correlate inversely with the corresponding phenylalanine levels in plasma and brain and the delay in plasma clearance response following a phenylalanine challenge. The maternal HPA effect on the fetus correlates directly with the degree of hyperphenylalaninemia, but only the ENU2 strain has impaired learning.

Alleles↗

Autochthonous mouse models for prostate cancer: past, present and future.

Prostate cancer continues to be the second leading cancer related death among men. In order to more fully develop effective prevention and intervention strategies for this prevalent disease, the underlying molecular mechanisms of initiation, progression and metastatic spread must be understood. To this end mouse models have an essential role in prostate cancer research in that they can closely mimic the pathological and biochemical features of the disease. In this review we discuss the history of autochthonous murine models of prostate cancer, the essentials of the idealized mouse model for prostate cancer and speculate on approaches towards this goal.

Animals↗